When trying to update a blueprint with network chests the game crashes. I can make a new blueprint without any issue. Error message below.

Error while running event item-network;;on_player_setup_blueprint (ID 70)
Index out of bounds:867 > 0.
Stack traceback:
[C]: in function 'set_blueprint_entity_tag'
item-network/src/NetworkChest.lua:91: in function
<item-network/src/NetworkChest.lua:74>

I was able to reproduce the crash and prevent it from crashing and released the fix in version 0.2.1.

However there is still a bug that updating a blueprint with network chests will not save network requests for the copied chests

So if I
1. Make a blueprint.
2. Click "Select new contents for the blueprint".
3. Select a new area containing network chests

The updated blueprint will contain all expected entities but the network chests are not configured with items.

This isn't for lack of trying. After searching through both the Factorio discord and forums I found this open issue from 2017 that still hasn't been fixed.
https://forums.factorio.com/88100

It sounds like it would take a significant rewrite of the blueprint mechanics to fix so nobody has prioritized this. I doubt it will be fixed any time soon.

Please let me know if you run into any more issues, otherwise I'll consider this bug fixed. Thanks for reporting!

Ah, well I rather not have settings saved then a crash in the middle of a blueprint session ;P Lost about 10 minutes of work in a edit world last night updating my blueprint book :P Thanks for the quick work :)